How to update my name under the icon which has my email as my surname is spelt incorrectly

It's great to see you here today, @usershanenarcis. 

Let's go to the Intuit Account Manager site so you can update your surname from there. Please keep in mind that the changes you'll make will apply to your other QuickBooks products. I'll guide you how.

1. Sign in to your QuickBooks Online (QBO) account.
2. Go to the User icon at the upper right of the screen. 
3. Select Manage your Intuit Account.
4. Choose Personal info. 
5. Click the arrow icon in the Name section. 
6. Update your Last Name. 
7. Select Save.

The screenshot below shows you the last six steps. 

Aside from the name, you can also change your email, user ID, or password within the Intuit Account Manager site. It helps you efficiently manage all of your data in one place. 

I'll lend a helping hand if you need anything else. Keep safe.